Method, Apparatus and a Forming Part For Casting a Concrete Product By Slipform Casting

ABSTRACT

Method and apparatus for casting a concrete product with a substantially horizontal slipform casting process, wherein the concrete mix is fed at least in one step through a limited cross-section moving progressively along with the cast, whereby the height of the product forming part ( 1 ) is changed during the cast. The invention also comprises a product forming part ( 1 ) having an adjustable height.

The present invention relates to slipform cast concrete products and toa slipform casting apparatus used in casting as well as to parts forforming the products to be cast. More precisely, the present inventionrelates to adjusting and changing the product height of a product to beslipform cast.

There are many different slipform casting methods and devices known inthe art. The most essential slipform casting solutions in use nowadaysare generally based on extruder or slipformer methods. In the solutionsbased on the extruder technique, the concrete mix is fed from theconcrete tank to feed screws that extrude the concrete to the molddefined by the casting bed and the side and upper plates. When castinghollow-core slabs, the feed screws are followed by hollow-core formingmandrels forming the hollow-cores to the concrete product to be cast.The compacting of the concrete product to be cast is effected by thevibrating and/or leveling motion of the side and upper plates and theforming of the hollow-core is secured by the compacting motion of thehollow-core mandrel. The casting machine moves along the casting beddriven by the reacting force, supported by the wheels of the machine.The finished cast product remains on the casting bed.

In the solutions based on the slipformer-technique, the concrete mix isfed with proceeding cast first to the lower part of the mold defined bythe side plates moving along with the casting machine and the castingbed. This first feed of the concrete is followed by vibrating shoes andforming mandrels that by vibrating the concrete mix compact the castconcrete mix and make the final form of the lower part of the product.During the second feed, concrete mix is fed onto the end parts of thehollow-core forming mandrels for casting the upper part of the productto be cast, said concrete mix to be compacted with a vibrating patelocated on top of the rear end. The finished product remains on thecasting bed.

The slipform casting is usually used for casting of longitudinalproducts, which are sawn to products with a suitable length afterhardening of the concrete.

A problem with the slipform casting devices known in the art is,however, that when the thickness of the product to be cast changes, thecasting machine must be lifted away from the casting bed for changingthe tools for forming the product and the tools for compacting. This istime consuming and expensive due to the production downtimes caused bythe changing.

Another alternative has been to provide a specific casting machine foreach product type to be cast, whereby the change of the product to becast can be performed quickly simply by changing the casting machine onthe casting bed. This alternative, however, needs a lot of capital to bebound in investments of equipment, especially, because the product rangeof the products to be cast is large.

By means of the present invention, it is possible to overcome theafore-mentioned drawbacks of the technique of prior art. In the solutionaccording to the invention, the height of the compacting plate and theforming part can be adjusted, whereby the height of the product to becast can be easily adjusted, enabling the production of products havingdifferent heights with one and the same slipform casting machine. Withthe solution of the present invention also, the height of the product tobe cast can be changed during the cast. In that way for example thelower portions required by the bathrooms can be cast directly to theproducts to be manufactured.

In this connection the forming part of the product refers to a part or asurface defining the cross-section of the concrete product to be cast.The term “compacting plate” in this connection refers to the surfacedefining the upper surface of the product, said surface compacting theupper surface of the product by a troweling and/or vibrating compactingmotion.

More precisely, the method in accordance with the present invention ischaracterized by what is stated in the characterizing part of claim 1,and the apparatus in accordance with the present invention ischaracterized by what is stated in the characterizing part of claim 4,and the product forming part in accordance with the invention ischaracterized in by what is stated in the characterizing part of claim7.

The invention will be described exemplified in more detail in thefollowing with reference to the enclosed drawings, wherein

FIG. 1A shows the location of the surface parts of one product formingpart in accordance with the invention, in its upper position, as an endview,

FIG. 1B shows a cross-sectional side view of one product forming part inaccordance with the invention, in its upper position,

FIG. 2A shows the location of the surface parts of one product formingpart in accordance with the invention, in its lower portion, as an endview,

FIG. 2B shows a cross-sectional side view of a product forming part inaccordance with the invention in its lower position,

FIG. 3 shows a schematic, cross-sectional side view of one slipformcasting machine in accordance with the invention, the product formingpart being in its upper position,

FIG. 4 shows a partial cross-sectional view of the rear part of theslipform casting machine of FIG. 3, at the region of the product formingpart, the forming part being in its lower position, and

FIG. 5 shows an example of a product cast by means of a castingapparatus in accordance with the invention, as a cross-sectional view atthe hollow-core.

FIGS. 1A and 1B show the construction of one product forming part inaccordance with the present invention, the forming part being in itsupper position. As it can be seen in FIG. 1A, the outer surface of theproduct forming part 1 is formed of an upper part 2 and a lower part 3,having substantially a U-formed profile and said upper part and lowerpart setting partly within each other. FIG. 1B illustrates the internalconstruction of the product forming part, whereby the upper part 2 andthe lower part 3 are connected with each other with a tie bar 4 and 4′.The tie bars 4, 4′ are attached turnably to the upper part and lowerpart of the core tube. The tie bars 4, 4′ are connected with each otherby means of an operating rod 5 extending outside the front edge of theproduct forming part 1. In the front edge of the product forming partthere is a front plate 6, attached to the lower part 3. The front plate6 prevents the concrete from entering into the product forming partduring the cast.

FIGS. 2A and 2B illustrate the product forming part according to FIGS.1A and 1B in its lower position. The product forming part 1 is moved toits lower position by pushing the operating rod 5 towards the productforming part, whereby the operating rod 5 moves inside the productforming part making the tie bars 4, 4′ to turn into the position shownin FIG. 2B. The motion of the tie bars 4, 4′ makes the upper part 2 ofthe product forming part to loosen from the front plate 6 as well as themotion of the upper part backwards and downwards. Correspondingly, bymoving the operating rod 5 away from the product forming part, theheight of the forming part can be increased.

In this way the height of the product forming part 1 can be changedbetween the upper position shown in FIGS. 1A and 1B and the lowerposition shown in FIGS. 2A and 2B. Only two positions of the productforming parts have been illustrated in said Figures, but is should beappreciated, that the core tube can be adjusted to any height betweenthe extreme positions.

A solution of the mechanical adjustment of the height of the productforming part is shown in FIGS. 1A, 1B, 2A and 2B. The adjustment of theheight of the product forming part in accordance with the invention,however, can be provided by means of a hydraulic and/or pneumatic heightadjusting device, preferably located inside the product forming part.

FIG. 3 shows a slipformer-type casting machine equipped with a productforming part 1 in accordance with the invention. In the example of thefigure, the product forming part is in its upper position. When using acasting machine of this kind of a slipformer-type, the concrete mix isfed from the feeding tank 7, 7′ via conveyors 8, 8′ to the foremost feedhopper 9 and to the rearmost feed hopper 10. Through the foremost feedhopper the concrete mix is guided to the lower part of the casting molddefined by the side plates proceeding along with the casting machine andthe casting bed. A vibrating shoe 11 and a forming tube 12 provide theform of the lower part of the product in the concrete. The forming tube12 is followed by the product forming part 1, onto which the concretemix for forming the upper part of the concrete product is fed from therearmost feed hopper 10. The feed hopper 10 is followed by thecompacting plate 13 defining the upper surface of the cast mold, saidcompacting plate 13 being located on top of the end portion of theproduct forming part 1, and compacting the concrete, as well as definingthe position of the upper surface of the concrete product to be cast.When the slipform casting machine proceeds, the finished product remainson the casting bed.

For adjusting the height of the product forming part 1, the slipformcasting machine is equipped with a hydraulic cylinder 14 for moving theoperating rod 5 of the product forming part in the direction shown bythe arrow beside the hydraulic cylinder 14, thus changing the height ofthe product forming part. For casting the lowered portion to the productto be cast, the slipform casting machine is equipped with a movablestand 15 having a feeding hopper 10 attached thereto on top of theproduct forming part 1 for feeding the concrete mix, as well as acompacting plate 13 and a vibrator 16 vibrating the same. The stand 15is attached to the slipform casting machine by means of tie bars 17,17′. The stand is movable with a hydraulic cylinder 18 in the directionshown by the arrow.

When the casting machine proceeds to the lowered portion to be cast, theheight of the product forming part 1 as well as the position of thestand 15 is changed to one shown by the partial cross-section of FIG. 4.Thus, the hydraulic cylinder 14 has moved the operating rod 5 of theproduct forming part towards the product forming part, whereby the upperpart of the product forming part 1 has moved backwards and lowered tothe desired height. At the same time, the hydraulic cylinder 18 hasdrawn the stand 15 towards itself, whereby the tie bars 17, 17′ haveturned backwards to the position shown in the Figure, and the stand 15has moved backwards and downwards to the desired height. Thereby thepositions of the feed hopper 10 and the compacting plate 13 have changedcorresponding to the height required by the cast of the lowered portion.In this way, the uniform thickness of the wall of the upper part of theconcrete product can be secured throughout the product.

The invention is not limited to the use of a hydraulic cylinder foradjusting the height of the product forming part and the compactingplate, but also other suitable devices, like for example pneumaticdevices can be used. The adjustment of the height of the product formingpart and the compacting plate can also be implemented manually, ifnecessary.

FIG. 5 shows an example of a hollow-core product with a lowered portion,made by a slipform casting apparatus in accordance with the invention.The cross-sectional view shows that at the lowered portion, thethickness of the upper wall of the product substantially corresponds tothe wall thickness of a product with normal height. Further, the lowerportion can be easily cast to a desired place with a desired length.

The solution in accordance with the invention is not limited only tocasting of lowered portions to a product to be cast. The invention alsoenables using of one and the same casting machine for casting productshaving different heights. In addition, with the solution in accordancewith the invention, also the thickness of the upper surface of theproduct to be cast can be easily changed.

Further, the product forming part in accordance with the invention isnot limited to the slipformer-type machine as shown in the example, butit can also be used in other types of slipform casting machines withsmall structural alterations.

Advantageously, the forming part of the product to be cast according tothe invention is the forming part for forming the hollow core to theproduct to be cast.

1. A method for casting a concrete product with a substantiallyhorizontal slipform casting process, whereby the concrete mix is fed atleast in one step through a limited cross-section moving progressivelyalong with the cast, wherein the distance between the upper surface (2)and the lower surface (3) of the hollow-core forming part (1) is changedduring the cast.
 2. A method in accordance with claim 1, wherein theposition of the compacting plate (13) with respect to the height ischanged during the cast.
 3. A method in accordance with claim 2, whereinthe position of the compacting plate (13) with respect of the height andthe height of the hollow-core forming part (1) are changedsimultaneously.
 4. An apparatus for casting a hollow-core concreteproduct with a substantially horizontal slipform casting process, saidapparatus comprising a limited cross-section moving progressively alongwith the cast, elements (7, 7′, 8, 8′, 9, 10) for feeding the concreteto the limited cross-section at least in one step, as well as elements(11, 12, 1) for forming the concrete product, wherein the apparatuscomprises means (14, 5, 4, 4′) for changing the distance between theupper surface (2) and the lower surface (3) of at least one hollow-coreelement (1) forming the concrete product.
 5. An apparatus in accordancewith claim 4, wherein the apparatus comprises means (18, 17, 17′, 15)for changing the height of the surface (13) defining the upper edge ofthe limited cross-section.
 6. An apparatus in accordance with claim 4wherein the apparatus comprises means (18, 17, 17′, 15) for changing theposition of at least one element (10) feeding concrete to the limitedcross-section.
 7. A hollow-core forming part (1) to be used in theslipform casting machine, wherein the outer surface of the hollow-coreforming part (1) is formed at least of two separate surfaces (2, 3)movable with respect to each other during the cast.
 8. A hollow-coreforming part (1) of claim 7, wherein the hollow-core forming partcomprises means (4, 4′) for attaching the surfaces (2, 3) with eachother movably with respect to each other.
 9. A hollow-core forming part(1) of claim 7, wherein the hollow-core forming part comprises means (4,4′, 5) for changing the location of the surfaces (2, 3) with respect toeach other so that the height of the product forming part changes.
 10. Ahollow-core forming part of claim 9, wherein the means for attachingwith each other the surfaces (2, 3) of the hollow-core forming partmovably with respect to each other, as well as the means for changingthe height of the hollow-core forming part (1) are implemented with atleast one hydraulic and/or pneumatic device.
 11. An apparatus inaccordance with claim 5, wherein the apparatus comprises means (18, 17,17′, 15) for changing the position of at least one element (10) feedingconcrete to the limited cross-section.
 12. A hollow-core forming part(1) of claim 8 wherein the hollow-core forming part comprises means (4,4′, 5) for changing the location of the surfaces (2, 3) with respect toeach other so that the height of the product forming part changes.
 13. Ahollow-core forming part of claim 12, wherein the means for attachingwith each other the surfaces (2, 3) of the hollow-core forming partmovably with respect to each other, as well as the means for changingthe height of the hollow-core forming part (1) are implemented with atleast one hydraulic and/or pneumatic device.